POW wrote:
Depends on how many kids you want. Women are about done having kids at 35, so think 2 years per kid (really should be closer to 3), plus 2 years for each kid and subtract it out. If you want 4 kids you probably need to have 3 before she turns 35 so 29 at the oldest. 35 is when you automatically become a high-risk pregnancy. They can have kids into their 40s so this is a guideline more than hard rule.
While age is important, what's more important is whether she will be a good mom. Will she help you kids work through their emotions, will she set good examples for them.
Also more important is that you like spending time with her and working with her. Because if you get married you are going to be spending a whole lot of time with her.
Keep in mind a lot of defects are more of a function of the father’s age.